The present disclosure relates to image forming apparatuses provided with a mechanism for moving a developing roller closer to and away from an image bearing member.
Some image forming apparatuses (for example, printers and copiers) include a photosensitive drum (image bearing member) and a developing unit. In addition, a gap roller is provided near each axial edge of a developing roller. The photosensitive drum bears a toner image on its peripheral surface. The developing unit includes the developing roller. The developing roller supplies toner to the photosensitive drum. In the printing operation, the photosensitive drum and the developing roller are brought into the state where the respective peripheral surfaces are opposed to each other with a predetermined gap therebetween (the state where each gap roller abuts against a non-image forming region of the peripheral surface of the photosensitive drum). In for example maintenance or jam-handling, on the other hand, when the developing unit is pulled out of the main body of the apparatus, the photosensitive drum and the developing roller are brought into the state where the respective peripheral surfaces are away from each other so as not to damage the peripheral surfaces.
For example, an image forming apparatus is suggested that includes a pressure member to bring the peripheral surface of the developing roller closer to the peripheral surface of the photosensitive drum. The developing unit is disposed to be horizontally movable within the main body. The developing unit is provided with a pin member on a side wall thereof. The pin member is guided by a horizontally elongated slot. The developing unit is urged in a horizontal direction by the pressure member. The pressure member presses the peripheral surface of the developing roller toward the peripheral surface of the photosensitive drum. Upon release of the pressure exerted by the pressure member, the developing roller moves away from the photosensitive drum.